Difference between revisions of "NodeRelationDatatype"

Revision as of 00:01, 1 February 2008

Introduction

This page describes the Higgins EntityRelationDatatype.

Definition

• An EntityRelationDatatype is a kind of URI Attribute Value Datatype
• A ContextIdDatatype MUST conform to the ABNF defined below
• It is comprised of a ContextIdDatatype URI combined with an optional identifier string called a EntityIdDatatype. The EntityIdDatatype may only be omitted when the Context identified by the ContextId contains exactly one Entity.

Two kinds of EntityIdDatatypes are defined: a URI-EntityIdDatatype (Hash URI) and XRI-EntityIdDatatype. The former is consistent with one of the two proposed W3C's Cool URIs approaches. The latter is an XRI as defined by XRI Syntax 2.0.

ABNF

The following ABNF defines a Higgins [[EntityId]. Rules not defined in this ABNF are defined in the ABNF for XRI 2.0 (which includes the IRI ABNF from RFC 3987).

EntityIdDatatype    = URI-EntityIdDatatype / XRI-EntityIdDatatype
URI-EntityIdDatatype = URI-ContextIdDatatype [ "#" EntityIdDatatype ]
XRI-EntityIdDatatype = XRI-ContextIdDatatype [ "//" EntityIdDatatype ]

Relationship to OpenID

• An EntityRelationDatatype's ContextId MAY use OpenID (2.0 only) for its authority segment. See ContextId for details.

Open Issues

• Should we combine EntityRelationDatatype and EntityIdDatatype?
  • In other words should we allow the ContextIdDatatype to be omitted if a EntityIdDatatype is present? (saves repeating the ContextIdDatatype when referring to another Entity in the same Context

See Also

• Attribute Value Datatype
• ContextIdDatatype
• EntityIdDatatype